Space stations should degrade over time

[connorjak]

There has been discussion on the discord for how to balance early and modular stations to avoid a situation where the player easily completes later contracts by adding a few small modules to their first station they ever launch. A “spare parts” resource would be an appropriate limiting factor on station lifetime. Right now if you replenish life support consumables along with your astronauts, and have ample solar panels, fuel cells, or nuclear power, you can use the same station indefinitely. Spare Parts would be consumed if your module is powered on / using a Process, and would be a somewhat significant mass and volume requirement over many days. If spare parts run out, the processes on the craft stop working.

I propose having Spare Parts be something where the usage rate accelerates over time from a minimum to a maximum rate. How long the rate takes to reach maximum would lengthen significantly with each station research node. This represents maturation of designs and maintenance of internal systems over time.

So, spare parts would likely be a minor proportion of consumables for a week-long mission, but the rate would increase to max in 2 weeks at lowest tech. Early stations would naturally be short lived, but not limited in part shape. At later tech levels, a long-lived station (or surface habitat) becomes viable. For example for a max Spare Parts tech level, it could take 15+ years before module reaches max usage rate, and the max usage rate could be lower than in early tech levels.

[connorjak]

This kind of game mechanic opens up interesting decisions for the player, such as the pros/cons of keeping old station/habitat modules active to benefit from their volume/processes/experiments vs keeping them shut down to conserve spare parts.

Also, depending on implementation, if the usage of spare parts happens even when parts are shut down, then this also introduces vehicle wear and tear (atomic oxygen, micrometeoroid, UV, radiation) as a mechanic. This kind of wear would limit the lifetime of, for example, a lifeboat reentry capsule.

If running out of spare parts results in random Process failures instead of instant failure for all, this also introduces process redundancy as a game mechanic. For example, a lunar habitat could need to subsist without spare parts for a few weeks if there is a failure of a resupply or crew rotation mission. If processes are duplicated around the habitat, loss of a single process isn't fatal.

[connorjak]

In-space manufacturing could be introduced as a tech-bounded process to convert manufacturing materials (much more space efficient than spare parts) into spare parts. Manufacturing materials could also be an output of ISRU.

[connorjak]

After further discussion, an efficiency decay like with solar panels does seem like a simpler way to make degradation happen. Maybe it would increase leak rate and make processes less efficient?